The present invention relates to an ignition system of the type having parallel ignition branches with an ignition spark gap, an auxiliary spark gap and a high voltage storage capacitor that is dischargeable via the ignition spark gap.
When designing an ignition system, it is a basic objective to produce sparks with a maximum ignitability. High ignitability is of particular significance in connection with the lean-burn engines at present being developed for fuel saving purposes, which use less readily igniting, sluggishly reacting fuel-air mixtures (lambda.gtoreq.1.4) and with the use of exhaust catalysts, which only accept misfirings to a limited extent, because unburned fuel entering the catalyst can lead to a combustion of the catalyst.
The use of high voltage storage capacitors and an auxiliary spark gap in conjunction with the actual spark plug spark gap (DE-OS No. 28 10 159) has made it possible to obtain energy-rich ignition sparks, which also advantageously convert most of their energy in the so-called spark head, i.e. in the break-through phase. However, in the case of such an arrangement, a high capacitance capacitor in the form of the storage capacitor must be charged to essentialy the ignition voltage, which is not possible with conventional transistor ignition systems due to their poor efficiency or even in the case of high voltage capacitor ignition systems with per se good efficiency, but low power with acceptable loading of the primary energy source (battery, electrical generator). This is mainly due to losses in the ignition coil and in the high voltage ignition distributor through which the secondary side of said coil is connected to the particular ignition branch.